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Nematosphaeropsis oblonga
Nematosphaeropsis oblonga Mudie, 1987
Taxonomic senior synonym: Nematosphaeropsis lemniscata, according to Wrenn (1988, p.142) — however, Mudie in Head and Wrenn (1992, p.16,18) retained Nematosphaeropsis oblonga.
Holotype: Mudie, 1987, pl.3, figs.4a–b; Head and Wrenn, 1992, pl.1, figs.3,6.
Age: Late Miocene-Early Pliocene
Original description (Mudie, 1987):
Nematosphaeropsis oblonga n. sp. (Plate 3, Figure 4a, b)
Holotype. Plate 3, Figure 4a, b; slide AGC 84031903, Z 55/1; Sample 611C-35-3, 48-50 cm; GSC 55318, Z 55/1.
Derivation of name. Latin oblonga (elongate).
Diagnosis. Cyst chorate, with a characteristically ellipsoidal central body, for which the length is at least 2 times longer than the width. The body bears numerous sturdy gonal processes at least as long as the body width. The processes terminate in short trifurcate distal branches, which are joined by double trabeculae and form undulating parallel lines. The archeopyle seems to be formed by loss of paraplate 3''.
Dimensions. Holotype: body length 30 µm, width 15 µm, gonal spine length 12 to 17 µm. Range in body length 35 to 28 µm, width 12.5 to 15 µm, spine length 12 to 25 µm. Ten specimens measured.
Description. A relatively large ellipsoidal cyst of Nematosphaeropsis whose distinctive elongate central body bears sturdy gonal spines with trifurcate branch tips interconnected by trabeculae. The longest trabeculae form undulating parallel lines, which appear to reflect parasutural boundaries. The archeopyle is trapezoidal and formed by loss of a single paracingular plate, presumably paraplate 3'' . Tabulation cannot be clearly discerned, but the number of paraplates delimited by the trabeculae is about the same as in N. labyrinthea.
Remarks. N. oblonga has the overall appearance of a N. labyrinthea cyst that has been compressed. However, numerous specimens of this ellipsoidal taxon coexist with normal spherical forms of N. labyrinthea; in these samples, the specimens of N. oblonga do not appear to be folded, damaged, or poorly preserved, and the spines are not broken or bent as would be expected if these cyst were merely poorly preserved forms of N. labyrinthea. The consistency of the elliptical body shape and morphology of the trabeculae processes, and the coexistance of these ellipsoidal cysts with typical spherical cysts of N. labyrinthea in sediments of late Miocene to early Pliocene age, makes N. oblonga a cyst form worthy of specific taxonomic differentiation.
Taxonomic senior synonym: Nematosphaeropsis lemniscata, according to Wrenn (1988, p.142) — however, Mudie in Head and Wrenn (1992, p.16,18) retained Nematosphaeropsis oblonga.
Holotype: Mudie, 1987, pl.3, figs.4a–b; Head and Wrenn, 1992, pl.1, figs.3,6.
Age: Late Miocene-Early Pliocene
Original description (Mudie, 1987):
Nematosphaeropsis oblonga n. sp. (Plate 3, Figure 4a, b)
Holotype. Plate 3, Figure 4a, b; slide AGC 84031903, Z 55/1; Sample 611C-35-3, 48-50 cm; GSC 55318, Z 55/1.
Derivation of name. Latin oblonga (elongate).
Diagnosis. Cyst chorate, with a characteristically ellipsoidal central body, for which the length is at least 2 times longer than the width. The body bears numerous sturdy gonal processes at least as long as the body width. The processes terminate in short trifurcate distal branches, which are joined by double trabeculae and form undulating parallel lines. The archeopyle seems to be formed by loss of paraplate 3''.
Dimensions. Holotype: body length 30 µm, width 15 µm, gonal spine length 12 to 17 µm. Range in body length 35 to 28 µm, width 12.5 to 15 µm, spine length 12 to 25 µm. Ten specimens measured.
Description. A relatively large ellipsoidal cyst of Nematosphaeropsis whose distinctive elongate central body bears sturdy gonal spines with trifurcate branch tips interconnected by trabeculae. The longest trabeculae form undulating parallel lines, which appear to reflect parasutural boundaries. The archeopyle is trapezoidal and formed by loss of a single paracingular plate, presumably paraplate 3'' . Tabulation cannot be clearly discerned, but the number of paraplates delimited by the trabeculae is about the same as in N. labyrinthea.
Remarks. N. oblonga has the overall appearance of a N. labyrinthea cyst that has been compressed. However, numerous specimens of this ellipsoidal taxon coexist with normal spherical forms of N. labyrinthea; in these samples, the specimens of N. oblonga do not appear to be folded, damaged, or poorly preserved, and the spines are not broken or bent as would be expected if these cyst were merely poorly preserved forms of N. labyrinthea. The consistency of the elliptical body shape and morphology of the trabeculae processes, and the coexistance of these ellipsoidal cysts with typical spherical cysts of N. labyrinthea in sediments of late Miocene to early Pliocene age, makes N. oblonga a cyst form worthy of specific taxonomic differentiation.